The invention concerns a device for measuring the temperature in a dust carrying gas stream having a temperature probe and a deflecting rod enclosing the probe at least partially and means for mounting the temperature probe and the deflecting rod within the gas stream substantially transversely to the flow direction.
Such devices are used for example for the measuring of the sifter temperature at coal crushers in coal fired power plants. With a known device of this type a bore is provided in the deflecting rod, in which bore the temperature probe is arranged. Due to this centered embedding of the temperature probe temperature variations in the coal dust carrying gas stream are detected only delayed in time. Since the output signal of the temperature probe is fed to the hot or cool air flap control of the coal crusher as a command variable, it is possible that there can be improper operation due to the delayed detection of the temperature variation and a corresponding slow response of the control. Further in case of the known arrangement it has to be provided that the temperature probe has a sufficient heat transfer contact with the inner wall of the bore. Due to the mechanical contact the oscillations impressed by the gas flow on the deflecting rod clamped at one end are transferred to the temperature probe, so that the life time thereof is decreased. Finally, the known device has the disadvantage that the wear of the deflecting rod cannot be detected during operation of the device and in that the state of wear can only be checked by the removal of the device from the measuring position.
First of all, it is the object of the present invention to provide a measuring device of the kind described above, with which a quick measurement and therewith an undelayed determination of a command variable is possible and with which simultaneously a substantially oscillation-free mounting of the temperature probe is possible.